A brief overview of photodynamic therapy in Europe.

Photodynamic effect was a chance discovery early in the 1900s, demonstrating the lethal effects of light activated chemicals on living cells. Although the application of the principles of photodynamic effect to patients' treatment and what became photodynamic therapy (PDT) was practiced in 1960s and 1970s, clinical trials were only started in the 1980s, following successful synthesis of clinically usable photosensitisers (drugs) and the manufacturing of light sources. We briefly review and highlight some of the landmarks of the development of clinical PDT in Europe.